Stephen Hawking, leading cosmologist and recently retired Lucasian Professor of Mathematics at Cambridge University, has co-authored a new book, The Grand Design. In it, he claims that the universe did not need God to create it.

Most cosmological models presume that when astronomers look at the objects most distant from earth, they are actually looking back in time. They aren't quite sure how galaxies first formed by natural processes, but they assume that "early" galaxies would look quite different from present-day ones. Thus, they were shocked to find fully matured galaxies so far away from so "long ago."

The further an investigation gets from testable science, the more speculative it becomes. How many inferences and ad hoc stories does it take before a scientific endeavor becomes science fiction? Two recent proposals from professional cosmologists step squarely across the boundary between conjecture-containing science and just plain conjecture.

Some scientists refer to certain dust and debris clouds in galaxies as star “incubators” because they think stars form naturally within them. But since the formation of a star from a compacted cloud would take far too long to observe even in many lifetimes, many references to stellar nurseries rely on circumstantial evidence and naturalistic reasoning.